When ticking the "export to soundcloud" option in the Session > Export > Export to Audio File(s)..., the window resizes to allow for the soundcloud options to appear.
Though, when unticking the option, the window doesn't resize to it's original height.

Steps To Reproduce

1) tick the "export to soundcloud" option in the Session > Export > Export to Audio File(s)..., => the window resizes
1) untick the "export to soundcloud" option => the window doesn't resize to its original height

Activities

Soundcloud upload has been disabled in 5.8-166-g9c016c619 because it does not work. Currently the checkbox is only visible in debug-builds (until it is fixed).

PS. Windows in general never shrink by themselves. The only exception in Ardour is currently the plugin-analysis tab and that can reduce the window below user-set size (which some consider a bug).

PPS. It may happen that built-in Soundcloud upload will be removed completely. Compared to entering username+password, it's faster to click "open folder" and drag/drop a file to a web-browser or to run a soundcloud uploader as post-export script.

Same behaviour for the official 5.8 and the latest git (5.8-203-ga199477) in debug mode (ardbg) at least.

Granted, this Soundcloud export is not a core feature, and could be removed plain and simple. I do use Soundcloud, though I've never used this export function because as you say, it's not even a huge time saver.

Though if this feature is kept, the window should resize back when unticking, as it resizes when ticking.

Another idea would be to put the id/pass somewhere in the preferences, and ticking would:
a) be grayed if these parameters are missing (e.g. with a little message "To use Soundcloud, please fill the infos in Preferences" on hover)
b) hence, not resize the window
This second solution would also make sense as these id/pass often stay the same. Maybe another user/pass setting in the Session Properties could override (if not empty) the main one for people who e.g. mix for different people, so the setting *could* be changed per-session, with a default in the preferences.